First Assessment Flashcards
What is the name of the earthing system that combines earth and neutral and then separates at the consumers intake?
TN-C-S
Where a three phase supply is provided for commercial or industrial properties, what is the voltage most likely to be?
400V
What is an exposed conductive part?
Trunking
What does the abbreviation ADS stand for?
Automatic Disconnection of Supply
Which of the following indicates how a circuit operates?
Circuit diagram
What would you use to determine how a piece of equipment works
User Guide
You need to install cable in a high temperature environment, MICC is specified, however the customer asks for a cheaper alternative. what would this be?
FP
For a new build domestic property, what would the main service fuse be rated at
100A
The term strapper cable is associated with?
Two way lighting
If cables are buried in a wall to more than 50mm in depth what further action should be taken?
None
When a TNS earthing system is used what element would carry a fault current
Metal Sheath
A domestic heater is rated at 4.5kW what would be the design current?
4.5kW = 4500W
4500 Divided by 230V = 19.56A
The cable that goes from the L1 side of a one way switch to your light fitting is known as:
Switch wire
What are the old Line conductor colors?
Red, Yellow, Blue
What is material is the compressed insulation in an MICC cable?
Magnesium Oxide
Using the singles method the switch feed from the DB goes to what terminal?
Common of the switch
Name the two types of fire alarm systems
Addressable & Conventional
The abbreviation 3L1.5 when using MICC would refer to
3 core light duty 1.5mm
Main protective bonding on an incoming water supply should be positioned at:
600mm from the intake position
Zs is = to
Ze +(R1+R2)
Failure to refer to the Wiring Regulations could result in which of the following:
Non-compliance with regard to the building regulations
+
non-compliance with regard to health & Safety
Which of the following is regarded as non-statutory
BS 7671
Which of the following came about through an act of parliament?
Health & Safety Act 1974
A double socket outlet is shown with a scale dimension of 15 mm. Using a scale of 1:100, calculate the actual dimension of the socket.
15mm x 100 = 1500mm / 1.5m
Which of the following indicates how a circuit operates
Circuit diagram
Which of the following would be beneficial in order to determine how a piece of equipment works?
User Guide
Which of the following would you refer to if you were installing unfamiliar equipment
Manufacturers instructions
Familiarizing yourself with which document means that you are following a code of practice?
BS 7671
An appropriate wiring method for a domestic installation would be:
PVC/SWA cables
An appropriate wiring method for a domestic installation would be:
PVC flat profile cable
A conductor used in the transfer of data is:
Fibre-optic
In high temperature environments, a cheaper alternative to mineral insulated cable would be?
FP
Which of the following is the most appropriate containment system fora low current application such as commercial lighting?
Power track.
Which of the following would be most appropriate regarding the final connection supplying a motor circuit
Flexible conduit
Which type of cable is most appropriate regarding the final connection to an immersion heater?
Flexible heat resistant cable
Which of the following is most appropriate containment system for heavy current applications?
Bus-bar systems
A steel conduit installation would be suitable for the following type of installation (2marks)
Commercial + Industrial
A steel trunking installation would be suitable for the following type of installation?
Commercial + Industrial
For a modern domestic property, the main service fuse should be rated at
100 A
For a modern domestic property, the meter tails should be
25mm
For a modern domestic property, which of the following is correct
Main earth conductor 16mm Main protective bonding conductor 10mm
Main protective bonding conductors provide bonding for what?
Extraneous conductive parts
A TN-C-S earthing system is also known as what?
PME SYSTEM
The term strapper cable is associated with what?
Two way-lighting
The cable that leaves the one-way switch to feed the light fitting is called what?
Switch wire
What is the normal size and rating of a lighting cable and protective device?
1.5 mm and 6A A
If cables are buried in a wall to more than 50mm in depth, what additional action should be taken
None
The maximum floor area an A1 circuit can serve is
100m²
An A2 circuit is known as what?
A radial Circuit 30 A or 32 A wired in 4.0mm²
Each power socket within a ring circuit can have
one unfused spur installed with a 2.5mm cable
In accordance with the wiring regulations, all power sockets rated at 20A or less must be given additional protection this means that;
a 30mA RCD must be in place
A kitchen is normally fed by it’s own ring main because:
it normally houses a lot of current drawing equipment
Which of the following applies to polarity
protective devices are installed in sequence highest to lowest from the main switch
Within a consumer unit, the highest rated circuit breaker should be positioned
Next to the main switch
When wiring up a spilt-board consumer unit, the downstairs lights should be positioned alongside
The upstairs sockets
Metal conduit and trunking elements of an installation are
Exposed conductive parts
The gas, water and central heating pipes of the building not forming part of the electrical installation are called:
Extraneous conductive parts
The act of connecting the exposed conductive parts of the installation to the main earthing terminal of the installation is called:
Earthing
According to the on-site guide all final circuits not exceeding 32A in a building supplied with a 230V TN earthing supply, shall have a maximum disconnection time not exceeding
0.4 seconds
Which of these symbols represents the total earth fault loop impedance:
Zs
A TNS earthing system makes use of which element to carry fault current?
Metal sheath
The purpose of earthing is to ensure
resistance path is low, fault current is high and disconnection is quick
Which of the following is an extraneous conductive part
Metal gas pipe
An industrial welder has been installed in a domestic garage but cannot operate because the type B circuit breaker protecting the circuit operates instantly. To correct this the circuit breaker needs:
to be replaced with a type D
The weakest link in the circuit designed to melt when too much over-current flows is one definition of
a fuse
The main service fuse needs to be able to withstand small supply surges and therefore will be which of the following types
BS88-2
Which of the following devices incorporates additional protection
RCBO
Which earthing system is not recommended for a petrol station?
TN-C-S
Calculate the total current demand for a domestic lighting circuit if it contains 20x100W filaments and the factor for diversity is 66%
20 x 100 = 2000
drop the voltage: 2000/230 = 8.69
8.69 x 0.66 = 5.7A
What % voltage drop is associated with power circuits
5%
A cooker can be fitted with a smaller cable after applying
Diversity
Refer to table F6 in the on-site guide and determine the maximum current associated with a 2.5mm cable which has been clipped direct.
27A
A domestic instantaneous heater is rated at 3kW. Given that the voltage is 230V work out the design current.
3kW = 3000w
3000w / 230 = 13.04 A
Refer to table F6 of the on-site guide and determine the voltage drop factor for a 4mm cable:
11 mV/A/m
Which of the following is the correction factor regarding ambient temperature
Ca
Which of the following is the symbol regarding current carrying capacity of the a cable?
Iz
Spike driven into the ground
TT System
